Writing process: Jumping around

In a New York Times article ( http://www.nytimes.com/2010/05/24/books/24type.html?ref=todayspaper), novelist Henry Roth’s writing process is described this way: “He’d work on a scene or character as long as it interested him and then jump to something else, not necessarily chronologically.” How do you write? Chronologically? As it comes to you? Or do you use a different system?